**Question:**

The dimensions of a room are 14 m × 10 m × 6.5 m. There are two doors and 4 windows in the room. Each door measures 2.5 m × 1.2 m and each window measures 1.5 × 1 m. Find the cost of painting the four walls of the room at Rs 35 per m2.

**Solution:**

The room has four walls to be painted.

Area of these walls $=2(l \times h)+2(b \times h)$

$=(2 \times 14 \times 6.5)+(2 \times 10 \times 6.5)$

$=312 \mathrm{~m}^{2}$

Now,

Area of the two doors $=(2 \times 2.5 \times 1.2)=6 \mathrm{~m}^{2}$

Area of the four windows $=(4 \times 1.5 \times 1)=6 \mathrm{~m}^{2}$

The walls have to be painted; the doors and windows are not to be painted.

$\therefore$ Total area to be painted $=312-(6+6)=300 \mathrm{~m}^{2}$

Cost for painting 1 m2 = Rs 35

Cost for painting $300 \mathrm{~m}^{2}=300 \times 35=$ Rs 10,500